Here is the latest Caml Weekly News, for the week of March 13 to 20, 2012.
Archive: https://sympa-roc.inria.fr/wws/arc/caml-list/2012-03/msg00186.htmlDeep in this thread, Xavier Leroy replied to many people:
Gerd Stolpmann writes: > The Random module is definitely not good enough (e.g. if you > know when the program was started like for a cgi, and the cgi reveals > information it should better not like the pid, the Random seed is made > from less than 10 unpredictable bits, and on some systems even 0 bits). Dario Teixeira adds: > I think the problem may be in finding a good source of randomness > that is common across all OSes. In Unixland this problem has > largely been solved: pretty much everyone supports /dev/random and > /dev/urandom. Windows does things differently, however. David Allsopp adds: > Does the source of randomness have to be common? The decision to use > a random seed doesn't need to be limited by a problem getting a good > cryptographically secure generator on a given OS - you'd simply > document that the implementation on that particular OS doesn't seed > with a good PRNG and await a patch from someone who may care in the > future, but at least the philosophy behind the decision is correct! We are also thinking of strengthening Random.self_init, for instance by using /dev/urandom when available. This said, for randomizing hashtables or other data structures, we do *not* need a cryptographically-strong PRNG: we're not generating an RSA key pair or some other situation where cryptographic quality is required; we're just making a mild DOS attack impractical. (Obligatory advertisement: if you're in need of cryptographically-strong random data, http://forge.ocamlcore.org/projects/cryptokit/ is what you need.)
Archive: https://sympa-roc.inria.fr/wws/arc/caml-list/2012-03/msg00190.htmlJean-Marc Alliot announced:
Everything is in the title. Just go to : http://www.alliot.fr/fbbdet.html.fr
Archive: https://sympa-roc.inria.fr/wws/arc/caml-list/2012-03/msg00203.htmlPietro Abate asked and Gabriel Scherer replied:
> In my application I'm using arrays all over, and lately I've discovered a > couple of bugs related to the fact that I was using the index of one array > to > get the element of another array. Since both indexes are int the compiler > could > not help me at all. Using private types it seems I can solve this problem > without loosing anything (??). Here is a proposal: https://gitorious.org/gasche-snippets/private-array-keys-type/blobs/master/private_array_key_types.ml It works by using a functor to generate "fresh" private types for keys. Note that the arrays themselves are still polymorphic (no IntArray FloatArray etc.). The user still has to use the discipline to produce a new application of ArrayMake each time she wants to use a different kind of array: if she only does `module A = ArrayMake(struct end)` and then use `A` for everything, there will be no additional safety guarantee.Later on, Pietro Abate asked and Gabriel Scherer replied:
> Thanks Gabriel, very nice solution. If I go this way, I guess there is > no way to access array elements using the usual a.(i) syntax (where i > = M.key i)... [...] > Is this a problem I can solve using a camlp4 decorator ? I don't think you need -- nor want to use -- a camlp4 extension. a.(i) is desugared into (Array.get a i) at a purely syntactical level in OCaml, so you could overload its behavior by changing the Array module in the typing environment. With my example you could write, for example: module A1 = ArrayMake(struct end) let () = let module Array = A1 in let k = A1.key in assert (A1.make 3 true).(k 2);; You could even define the ArrayMake functor so that it returns a structure with an Array submodule. You would then write, using 3.12 "local open" syntax: module A1 = ArrayMake(struct end) let () = let open A1 in assert (Array.make 3 true).(k 2) That said, I don't think that the slight readability benefit of writing a.(i) instead of (get a i) will outweigh the confusion among your readers that don't understand what you're doing with this weird Array stuff.
Archive: https://sympa-roc.inria.fr/wws/arc/caml-list/2012-03/msg00212.htmlAlain Frisch announced:
Another great event for the OCaml community, to be held in conjunction with ICFP in September... Note that users, not only researchers, are particularly welcome to propose a presentation, and of course to attend the workshop. -- Alain ======================================================================= CALL FOR PRESENTATIONS ACM SIGPLAN Workshop on ML Thursday, September 13th, 2012, Copenhagen, Denmark (co-located with ICFP) http://www.lexifi.com/ml2012 ======================================================================= The ML family of programming languages includes dialects known as Standard ML, OCaml, and F#. These languages have inspired a large amount of computer-science research, both practical and theoretical. This workshop aims to provide a forum where users, developers and researchers of ML languages and related technology can interact and discuss ongoing research, open problems and innovative applications. The format of ML 2012 will continue the return in 2010 and 2011 to a more informal model: a workshop with presentations selected from submitted abstracts. The workshop will not publish proceedings, so any contributions may be submitted for publication elsewhere. We hope that this format will encourage the presentation of exciting (if unpolished) research and deliver a lively workshop atmosphere. SCOPE ----- We seek research presentations on topics related to ML, including but not limited to * applications: case studies, experience reports, pearls, etc. * extensions: higher forms of polymorphism, generic programming, objects, concurrency, distribution and mobility, semi-structured data handling, etc. * type systems: inference, effects, overloading, modules, contracts, specifications and assertions, dynamic typing, error reporting, etc. * implementation: compilers, interpreters, type checkers, partial evaluators, runtime systems, garbage collectors, etc. * environments: libraries, tools, editors, debuggers, cross-language interoperability, functional data structures, etc. * semantics: operational, denotational, program equivalence, parametricity, mechanization, etc. Three kinds of submissions will be accepted: Research Presentations, Experience Reports and Demos. * Research Presentations: Research presentations should describe new ideas, experimental results, significant advances in ML-related projects, or informed positions regarding proposals for next-generation ML-style languages. We especially encourage presentations that describe work in progress, that outline a future research agenda, or that encourage lively discussion. These presentations should be structured in a way which can be, at least in part, of interest to (advanced) users. * Experience Reports: Users are invited to submit Experience Reports about their use of ML languages. These presentations do not need to contain original research but they should tell an interesting story to researchers or other advanced users, such as an innovative or unexpected use of advanced features or a description of the challenges they are facing or attempting to solve. * Demos: Live demonstrations or short tutorials should show new developments, interesting prototypes, or work in progress, in the form of tools, libraries, or applications built on or related to ML. (Please note that you will need to provide all the hardware and software required for your demo; the workshop organizers are only able to provide a projector.) Each presentation should take 20-25 minutes, except demos, which should take 10-15 minutes. The exact time will be decided based on the number of accepted submissions. SUBMISSION INSTRUCTIONS ----------------------- Submissions should be at most two pages, in PDF format, and printable on US Letter or A4 sized paper. Submissions longer than a half a page should include a one-paragraph synopsis suitable for inclusion in the workshop program. Submissions must be uploaded to the following website before the submission deadline (2012-06-04): https://www.easychair.org/conferences/?conf=ml2012 For any question concerning the scope of the workshop or the submission process, please contact the program chair (alain AT frisch.fr). IMPORTANT DATES --------------- * 2012-06-04: Submission * 2012-07-13: Notification * 2012-09-13: Workshop PROGRAM COMMITTEE ----------------- Alain Frisch (chair) (LexiFi) Anders Schack-Nielsen (SimCorp) Cedric Fournet (Microsoft Research) Francois Pottier (INRIA) Gian Ntzik (Imperial College) Jeremy Yallop Keiko Nakata (Institute of Cybernetics, Tallinn) Matthias Blume (Google) Oleg Kiselyov Stephen Weeks (Jane Street Capital) Tomas Petricek (University of Cambridge) STEERING COMMITTEE ------------------ Andreas Rossberg (Google) Chung-chieh Shan (Cornell University) Eijiro Sumii (chair) (Tohoku University) Jacques Garrigue (Nagoya University) Matthew Fluet (Rochester Institute of Technology) Robert Harper (Carnegie Mellon University) Yaron Minsky (Jane Street)
Archive: https://sympa-roc.inria.fr/wws/arc/caml-list/2012-03/msg00216.htmlThomas Gazagnaire announced:
We (OCamlPro) are looking to recruit an excellent software engineer. OCamlPro is a small French company located near Paris. It is devoted to promote the use of OCaml to IT professionals, as a way to make industrial software more reliable. We participate to the development of OCaml and we create new tools and libraries to facilitate the use of OCaml in large industrial software projects (such as the TypeRex development studio). We especially seek for candidates with: * strong problem solving skills, ie. the ability to find clean and elegant solutions to complex engineering problems; * very strong experience of developing applications in OCaml (at least 3 years); * good understanding and knowledge of the OCaml compilers and runtimes' internals; * experience in extending, contributing and maintaining open-source libraries and tools; * the determination to work with our customers to understand and analyze their needs, and deliver great products to fulfill them. If you are interested by this position, please email your C.V. with a description of some of your best accomplishments to: contact AT ocamlpro.com Thanks,  http://www.ocamlpro.com  http://www.typerex.org
Archive: https://sympa-roc.inria.fr/wws/arc/caml-list/2012-03/msg00225.htmlDaniel Bünzli announced:
I'd like to announce the release of Cmdliner 0.9.1, React 0.9.3, Rtime 0.9.2, Uuidm 0.9.4, and Xmlm 1.1.0. There's a mix of bug fixing and small feature additions. Consult the individual release notes given below. But foremost all the modules now support OASIS and use setup.ml for the distribution. Thanks to Sylvain for his work and taking time to respond to my questions. The tarballs were tested with `odb.ml` and seem to install fine that way. Before they eventually find their way into oasis-db (it doesn't support oasis 0.3 yet) you'll find a few lines here  that you can add to your `packages` file to access them directly. Best, Daniel  http://erratique.ch/software/odb-packages.txt * Cmdliner v0.9.1 http://erratique.ch/software/cmdliner - OASIS support. - Fixed broken `Arg.pos_right`. - Variables `$(tname)` and `$(mname)` can be used in a term's man page to respectively refer to the term's name and the main term name. - Support for custom variable substitution in `Manpage.print`. - Adds `Term.man_format`, to facilitate the definition of help commands. - Rewrote the examples with a better and consistent style. # Incompatible API changes - The signature of `Term.eval` and `Term.eval_choice` changed to make it more regular: the given term and its info must be tupled together even for the main term and the tuple order was swapped to make it consistent with the one used for arguments. * React v0.9.3 http://erratique.ch/software/react - OASIS support * Rtime v0.9.2 http://erratique.ch/software/rtime - OASIS support. * Uuidm v0.9.4 http://erratique.ch/software/uuidm - OASIS support. - New functions `Uuidm.v3` and `Uuidm.v5` that generate directly these kinds of UUIDs. - New function `Uuidm.v4_gen` returns a function that generates version 4 UUIDs with a client provided random state. Thanks to Lauri Alanko for suggesting that `Random.make_self_init` may be too weak for certain usages. * Xmlm v1.1.0 http://erratique.ch/software/xmlm - OASIS support. - Fixes a bug in the UTF-16 decoder. - Fixes a bug in `Xmlm.make_output` with a custom function. Thanks to Konstantinas Myalo for the report and the patch. - New optional argument `decl` to `Xmlm.make_output` to control whether the XML declaration should be output. - New function `Xmlm.output_depth`, returns the current element nesting level.
Archive: https://sympa-roc.inria.fr/wws/arc/caml-list/2012-03/msg00217.htmlPhilippe Veber asked and Jérémie Dimino replied:
> Say that you'd like to search a regexp on a file with lines so long > that you'd rather not load them entirely at once. If you can bound > the size of a match by k << length of a line, then you know that you > can only keep a small portion of the line in memory to search the > regexp. Typically you'd like to access substrings of size k from left > to right. I guess such a thing should involve buffered inputs and > avoid copying strings as much as possible. My question is as follows: > has anybody written a library to access these substrings gracefully > and with decent performance? Cheers, You can use a non-backtracking regexp library to find offsets of the substrings, then seek in the file to extract them. You can use for example the libre library from Jérôme Vouillon . It only accept strings as input but it would be really easy to make it work on input channels (just replace "s.[pos]" by "input_char ic").  http://sourceforge.net/projects/libre/ https://github.com/avsm/ocaml-re.git
Archive: https://sympa-roc.inria.fr/wws/arc/caml-list/2012-03/msg00177.htmlBob Zhang asked and Gerd Stolpmann replied:
> I noticed that Godi can pretty print cmi files, is there already > libraries parsing cmi files? Yes, toplevellib.cma (i.e. the ocaml toploop). It's a silly trick. Run the toploop and do module M = <NameOfTheCMI>;; and the toploop responds.Gerd Stolpmann later suggested and David Brown added:
> I think you can also "use" ocamlc -i for it, maybe easier to wrap. ocamlc -i will print out all of the types of the .ml file, not just the interface. It's useful, but not necessarily what is wanted. The top trick doesn't work if the code isn't byte-compiled and has the consequence of running the module. It would be handy to be able to actually just dump out the .cmi file, especially in cases, such as prebuilt packages that include the .cmi but left out the .ml files.rixed also replied to the original question:
Yes you can do this using the compiler libs (not installed by default but debian have these in a separate package). For an exemple of use see for instance the small tool displaying mli signatures from this git repo: git clone http://git.gitorious.org/ocalme/cmidump.gitRaphael Proust also suggested:
There is the cmigrep tool found on http://homepage.mac.com/letaris/ I have no idea about current status though; http://jun.furuse.info/hacks seems to imply it works on 3.12.Hongbo Zhang then said and Mehdi Dogguy replied:
> I tried, it does not compile, but it would be not hard to fix, I > guess. In Debian, we apply the following patches to compile it: http://patch-tracker.debian.org/package/cmigrep/1.5-9 FWIW, it compiles and runs perfectly well with any OCaml >= 3.10.
Thanks to Alp Mestan, we now include in the Caml Weekly News the links to the recent posts from the ocamlcore planet blog at http://planet.ocamlcore.org/. Ocsigen Js_of_ocaml 1.1 released: http://ocsigen.org/ Ocsigen Server 2.0.4 released: http://ocsigen.org/ Interval computation library 1.1: http://caml.inria.fr/cgi-bin/hump.cgi?contrib=805 OCaml MySQL Protocol 0.4: http://caml.inria.fr/cgi-bin/hump.cgi?contrib=804 OCaml MySQL Protocol 0.4 available: https://forge.ocamlcore.org/forum/forum.php?forum_id=828 Spring release: http://erratique.ch/software ML workshop 2012: call for presentations!: http://www.lexifi.com/blog/ml2012 Unix.open_process* and file descriptors: http://blog.rastageeks.org/ocaml/article/unix-open_process-and-file barbra: https://forge.ocamlcore.org/projects/barbra/ whenjobs 0.7.0 released: http://rwmj.wordpress.com/2012/03/13/whenjobs-0-7-0-released/
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